Physical Layer Security in Intervehicular Cognitive Relaying Communication Systems

This paper investigates the secrecy performance of an intervehicular cognitive relaying network. We assume that the primary receiver (PU) in the primary network is fixed, whereas the secondary source, secondary relay, secondary destination, and eavesdropper are moving vehicles. Considering such scenario, the channel between fixed node and vehicle node is modeled as Rayleigh fading, while the vehicle-to-vehicle channels are modeled as double-Rayleigh fading. In order to analyze the impact of eavesdropper channel and maximum tolerable interference level at PU, we firstly derive the tight closed-form expression of the secrecy outage probability (SOP) for the considered system. Moreover, to extract further insights, the asymptotic SOP expression in the high signal-to-noise ratio (SNR) regime is also deduced, which reveals that the eavesdropper has detrimental effect on the system secrecy performance and even reduces the system secrecy diversity order to zero. Lastly, we validate our analytical finding via simulations.